Control of size and heat affected zone for fine pitch wire bonding

Abstract

The amount of a terminal portion of bonding wire which is melted to form a free air ball for ball bonding and the temperature rise in the bonding wire adjacent the free air ball is limited by quenching of the wire and free air ball with a flow of a gas which also effectively removes heat applied to the wire. Since the amount of melting of the bonding wire can be closely regulated, reduction of size and improvement of uniformity of the free air ball can be obtained for ball bonding at pitches of less than ninety mils even when bonding wire of reduced diameter is employed. Quenching of the bonding wire adjacent to the free air ball also limits the temperature rise in the bonding wire and the extent of a heat affected zone having less tensile strength and stiffness to less than one micron and with reduced grain enlargement. Thus wire bonding is provided for electronic packaging of increased reliability, potential functionality, increased manufacturing yield and reduced process complexity.

Dependencies are inferred from the claim text.